r - Assign Colour to each line in ggplot2 -

hello people, trying use geom_line function create line graphs in r. want assign specific colours each line , unable so. when try manually assign colours colour names variables , in legend arranged alphabetically. if don't don't colours @ all. looked around on web , noticed there should grouping variable colours can assigned. unfortunately, in dataset here, each column corresponds different variable. not sure transposing dataset work because trying plot these variables against >2000 values on x-axis. think missing simple here.

ggplot(data=data, aes(xvar))+ geom_line(aes(y=var1))+ geom_line(aes(y=var2))+ geom_line(aes(y=var3))+ geom_line(aes(y=var4)) 

please feel free redirect section if has been answered before. appreciated.

i able manually without using ggplot2 function code follows:

plot(data$wavelength,data$var1,col="green") par(new=t) plot(data$wavelength,data$var2,col="red") par(new=t) plot(data$wavelength,data$var3,col="purple") par(new=t) plot(data$wavelength,data$var4,col="black") par(new=f) 

here shortcuts may helpful:

dat <- data.frame(wave = 1:100,                   var1 = sort(rnorm(100)),                   var2 = sort(rnorm(100, 1)),                   var3 = sort(rnorm(100, 2)))  plot(dat$var3, col = 'blue', type = 'l') lines(dat$var2, col = 'red') lines(dat$var1, col = 'green') 

library(reshape2) library(ggplot2)  dat.m <- melt(dat, id.vars = 'wave')  ggplot(dat.m, aes(wave, value, colour = variable)) + geom_line() 

ggplot(dat.m, aes(wave, value, colour = variable)) + geom_line() +    scale_colour_manual(values = c('pink','orange','white'))